Warren Distinguished Lecture Series

Special Vardoulakis Lecture

Lyesse Laloui
School of Architecture, Civil, and Environmental Engineering, Ecole Polytechnique Federale de Lausanne

Abstract

Catastrophic landslide events in unsaturated soils causing massif destruction and loss of lives are numerous and recurrent around the world. Rainfall-induced wetting processes in soil slopes can lead to significant contractive deformations associated with changes in stress states. Local stress redistributions within a slope can enable in certain conditions the development of a progressively formed failure mechanism. A physically-based, hydromechanically coupled continuum modelling approach is presented that is suitable for the study of various coupled physical processes and instability phenomena in variably saturated soil slopes subjected to rain infiltration. A transient flow-displacement-stress simulation with a finite element slope model representative for a landslide-prone volcanic ash slope above a pozzolana quarry in Costa Rica is performed to demonstrate the capacity of the modelling approach to deal with the physical processes and instability phenomena due to rain infiltration. An extensive laboratory testing programme was carried out to characterise the behaviour of the volcanic ash and to calibrate the various components of the model. Results of the slope model simulation demonstrate the important role of wetting and drying cycles, slope and bedrock geometry in the time evolution of matric suction and wetting-induced deformation. Instability phenomena are closely related to changes in matric suction. Moreover, it is observed that the pore-collapse upon wetting enhances the development of a localised shear failure mechanism in unsaturated conditions. In combination with analytical considerations, the obtained results contributed to the establishment of a prototype monitoring and an early-warning system.

About the Speaker

Dr. Lyesse Laloui is chaired professor and Director of the Soil Mechanics Laboratory at the Swiss Federal Institute of Technology, EPFL, Lausanne, where he developed a large group in the areas of Soil Mechanics, Geoengineering, and CO2 sequestration. He is also Director of the Civil Engineering Section. His main research interests are in geomechanics (constitutive and numerical modelling of multiphysical coupling processes, laboratory advanced testing), and environmental and energy sustainability (nuclear waste underground storage, petroleum geomechanics, CO2 geological sequestration, geothermal energy). His most know work addresses the effective stress principle for unsaturated soils, thermodynamic mixture modelling for unsaturated soils, experimental and modelling work on thermo-mechanics of clays and investigations of heat exchanger piles.

Lorenz G. Straub Award Ceremony

Eckart Meiburg
Center for Interdisciplinary Research in Fluids
Department of Mechanical Engineering, University of California at Santa Barbara

Abstract

We will present an overview of high-resolution, Navier-Stokes based simulations of gravity and turbidity currents. The turbidity currents are driven by particles that have negligible inertia and are much smaller than the smallest length scales of the buoyancy-induced fluid motion. For the mathematical description of the particulate phase an Eulerian approach is employed, with a transport equation for the particle-number density. We will discuss differences between two- and three-dimensional turbidity current dynamics, and we will introduce some effects due to complex topography. Results will be shown regarding the unsteady interaction of a gravity current with a submarine structure, such as a pipeline. Furthermore, we will discuss the linear stability problem of channel and sediment wave formation by turbidity currents.

Treavor H. Boyer
Environmental Engineering Sciences, University of Florida

[Replay not available]

Abstract

The current approach to wastewater management wastes valuable resources – potable water, fertilizer quality nutrients, and energy, while at the same time pollutes the biosphere with excess nutrients, contaminants of emerging concern, and greenhouse gases. The current failure of wastewater management is attributable to combining disparate waste streams (e.g., greywater, feces, and urine) and a ‘one size fits all’ approach to treatment. Of the waste streams that make up wastewater, urine accounts for approximately 1% of wastewater by volume yet urine contributes greater than 50% by mass of the nitrogen, phosphorus, potassium, and pharmaceuticals to wastewater. As a result, urine source separation and treatment has been proposed as a sustainable alternative to conventional wastewater management because it has the potential to conserve water and energy, recover nutrients for beneficial use, and protect ecological and human health from pharmaceutical contaminants. Despite the promises of urine separation and treatment, it has not been widely implemented because of an absence of engineering strategies that are efficient in contaminant removal, practical to implement, and acceptable to society.

This presentation will highlight ongoing work in our group that seeks to advance both basic understanding and practical implementation of urine source separation. Topics and data for discussion will include improving the function of waterless urinals, selective recovery of nutrients from urine, separation of pharmaceuticals from urine, urine as fertilizer for turfgrass, strategies for collecting urine from buildings and sporting venues, and thoughts on the future of urine separation.

Alexander Chudnovsky
Department of Civil and Material Engineering, University of Illinois at Chicago

Abstract

A domain of dense strain localization surrounding and preceding the crack growth (plastic zone, damage zone or, in general, process zone (PZ)) is commonly observed in engineering materials. A closely coupled system of crack and PZ is referred to as crack layer (CL). Slow CL growth results from a) strong interactions between the crack, process zone (PZ) and the rest of the solid, and b) degradation processes of the PZ material. CL thermodynamic forces are conventionally presented as the negative derivative of Gibbs free energy of the solid containing CL with respect to CL parameters.  CL constitutive equations are formulated in form of Onsager equations, i.e., linear relations between the rates of crack and PZ growth and corresponding thermodynamic forces. Numerical solution of CL growth equations suggests a complex kinetics of slow CL growth. Continuous, discontinuous and transient CL growth predicted by CL model is experimentally confirmed.

The experimental examination of CL model is conducted using specially design experimental setup, since it is difficult to observe in-situ the mechanisms and kinetics of crack and PZ growth in non-transparent materials. The micro-mechanisms of CL growth is observed by means of optical and SEM microscopy. It is shown that the complexity of CL growth is related to a ductile-brittle transition taking place on the micro scale within PZ. Applications of CL model and the challenges for accelerated testing for lifetime are also discussed.

Biography

Presently A. Chudnovsky is UIC Distinguished Professor Emeritus and Director of Fracture Mechanics & Materials Durability Laboratory at Civil and Materials Engineering Department of The University of Illinois at Chicago. Professor Chudnovsky received his education in the former Soviet Union. In 1980 he became a professor at Case Western Reserve University, Cleveland, OH. From 1987 till 2010 he is Professor of Mechanics and Materials at Civil and Materials Engineering Department of UIC and Director of UIC Fracture Mechanics and Materials Durability Laboratory. In 2001 he is awarded the title of UIC Distinguished Professor.

Among scientific accomplishments of Professor Chudnovsky there are Mathematical Theory of Elastomers, Entropy Criterion of Local Failure, Statistical Fracture Mechanics, Crack Layer Model and more recent Geometrical Modeling of Material Aging. He has published a monograph (in Russian) and more than 300 technical papers; graduated 42 Ph.D. students. Prof. Chudnovsky has a wide range of research interests: Statistical Thermodynamics and Thermodynamics of Irreversible Processes, Critical Phenomena, Fracture Mechanics, Application of Probability and Statistics in Engineering Design, Materials Durability and Structural Reliability. In his consulting services he conducts forensic studies, reliability assessments of engineering structures and lifetime prediction for metals, polymers, composites and rocks, as well as for new breed of materials for microelectronics and photonics applications.

Jean-Pascal Planche
VP Transportation Technology, Western Research Institute, University of Wyoming

Abstract

The Western Research Institute has been working for more than 30 years in the fields of asphalt and heavy oil chemical characterization. In the course of its current FHWA funded Fundamental Properties of Asphalts and Modified Asphalts research program, WRI has gone one step further in the fundamental understanding and practical characterization of asphalt binders. The whole concept is based on testing miniaturization.  Out of more than twenty research products to be released from this research contract, the five main products, which will be discussed in this presentation, deal with obtaining the most relevant information on asphalt chemical composition, evolution and properties from very small samples of binders.

From a fundamental researcher standpoint, they allow pinpointing which asphalt fractions are responsible for its chemical and viscoelastic changes and allow measurement of aging kinetics and changes in rheological properties under various conditions of temperature and pressure. From a practitioner standpoint, they offer new possibilities for quickly evaluating the rheological properties at low temperatures and the aging sensitivity of tank samples, as well as mix plant aged samples, either warm or hot, and even field aged samples.  

Michel Bruneau
Department of Civil, Structural and Environmental Engineering, University at Buffalo

Abstract

New structural systems and concepts can add to the Structural Engineer’s “toolbox,” providing him/her with an ever increasing range of solutions to meet increasingly complex design challenges. In keeping with this analogy, the objective of this presentation is to provide an overview of some recently developed “tools” that can enrich this toolbox. Systems to be discussed include Steel Plate Shear Walls (SPSWs), Perforated SPSWs (P-SPSWs), Tubular Eccentrically Braced Frames (TEBFs), Concrete Filled Steel Tubes (CFSTs), Structural Fuses (SFs), Rocking Frames (RFs), and Self-Centering SPSWs (SCSPSWs). The presentation will focus on the research results of former graduate students with whom the author has had the pleasure to work.

About the Speaker

Michel Bruneau, Ph.D., P.E., professor of civil, structural, and environmental engineering (CSEE) at the University at Buffalo, N.Y., is the 2012 recipient of the prestigious AISC T.R. Higgins Lectureship Award. Dr. Bruneau has conducted research on the evaluation and retrofit of existing steel bridges and buildings subjected to destructive forces, as well as on the development of new design concepts capable of providing satisfactory seismic-resistance, blast-resistance, or both (as multi-hazard resistant concepts). He has conducted reconnaissance visits to numerous disaster stricken areas, is a member of various AISC and CSA specifications-writing committees, and served as Director of the Multidisciplinary Center for Earthquake Engineering Research, a National Center of Excellence funded by the National Science Foundation, the Federal Highway Administration and others. Dr. Bruneau has authored over 400 technical publications, including the textbook “Ductile Design of Steel Structures,” (http://www.michelbruneau.com/DuctileDesign.htm) and two fiction books. He has received many awards for his technical work (as well as for his latest novel, http://www.michelbruneau.com/MB-Literature.htm).

The AISC T.R. Higgins Lectureship Award is presented annually by the American Institute of Steel Construction (AISC) and recognizes an outstanding lecturer and author whose technical papers are considered an outstanding contribution to the engineering literature on fabricated structural steel.

Lutgarde Raskin
Department of Civil and Environmental Engineering
University of Michigan

Abstract

The co-existence of multiple contaminants (e.g., nitrate, perchlorate, arsenic, uranium, chromium, and chlorinated organics) in groundwater sources often results in the closure of wells or the need for expensive treatment schemes.  Advanced physico-chemical processes, such as reverse osmosis and ion exchange are capable of removing multiple contaminants simultaneously, but are often cost-prohibitive due to the requirement of treatment of generated concentrated wastes or regeneration of exhausted materials. Microbial processes provide attractive treatment alternatives as several contaminants can be converted to innocuous compounds through microbial conversions. In addition, microbes often can mediate the conversion of contaminants to less toxic and easily separable solid phases in the same treatment system.

I will present how we have developed and optimized fixed-bed anaerobic bioreactor systems over the past 12 years to simultaneously remove several co-existing contaminants, including nitrate, perchlorate, arsenic, and uranium.  Examples from laboratory, pilot, and demonstration scale studies will be shown.  The presentation will also cover how microbial community characterization has been helpful in system optimization.  Finally, the need for appropriate post-treatment when implementing microbial treatment technologies to consistently produce high quality finished drinking water will be illustrated using disinfection studies with culture-independent molecular techniques. 

Julian Marshall
Department of Civil Engineering, University of Minnesota

Abstract

According to the World Health Organization, urban air pollution is one of the top 15 causes of death globally (one of the top 10 causes in high-income countries), responsible for ~ 1.7% of deaths annual (high-income countries, 2.1%). How can we reduce those health effects? This presentation will discuss three investigations into that question: (1) Urban form describes the physical layout of an urban area – for example, city shape, population density, and “patchiness” of urban growth. We have found that air pollution is related to urban form, for cities in the US and internationally, raising the question of whether urban planning can help cities meet air quality goals. (2) In developing countries, indoor air can be especially polluted, owing to combustion of solid fuels for heating and cooking. In a rural village in Karnataka, India, we have conducted a randomized control trial of a higher-efficiency stove, to test whether the stove improves indoor air pollution, health effects, and climate-relevant emissions. (3) We have explored how shifting from conventional fuels to bio-fuels changes the locations of emissions, thereby impacting air quality and who is exposed to pollution. The goal is to understand whether biofuels are better for human health and the environment than the fossil fuels they displace. A constant theme through these topics is environmental justice: which groups have higher exposures to air pollution, and how exposure correlates with demographic attributes such as race and income.

About the Speaker

Dr. Julian Marshall is an Assistant Professor of Environmental Engineering in the Department of Civil Engineering at University of Minnesota. His research involves modeling and measuring exposure to air pollution. Marshall earned his BSE with High Honors in Chemical Engineering from Princeton University, and his MS and PhD in Energy Resources from UC Berkeley. His publications include “most downloaded” articles from the top journal in the field: Environmental Science & Technology and Atmospheric Environment. At UMN, Marshall co-directs the Acara Challenge and the Peace Corps Masters International program in Civil Engineering, and is the co-advisor for the student chapter of Engineers Without Borders. His honors include a McKnight Land-Grant Professorship. Marshall currently is being evaluated for advancement from assistant to associate professor.